1. Field of the Invention
The present invention relates to a vibration generating apparatus.
2. Description of the Related Art
A vibration generating apparatus, a component converting electrical energy into mechanical vibrations through the generation of electromagnetic force, is commonly mounted in a mobile phone to be used to silently notify a user of call reception by transferring vibrations thereto.
Meanwhile, in accordance with rapid growth in the mobile phone market and the trend for adding functionality to mobile phones, mobile phone components having a compact size and a high degree of quality have been required. In this situation, the demand for the development of a vibration generating apparatus having a novel structure capable of overcoming the disadvantages of existing vibration generating apparatuses, and having significantly improved quality with respect thereto, has increased.
In addition, as the release of smartphones has rapidly increased, a touchscreen scheme has been adopted therein, such that in addition to silently notifying a user of call reception, vibration generating apparatuses have been used in order to generate vibrations when the touchscreen is touched.
Degrees of performance required of the vibrations generated when the touchscreen is touched in particular, are as follows. First, since vibrations are generated more frequently in devices having touchscreens than in phones merely vibrating at the time of call reception, an operational lifespan of a vibration generating apparatus should be increased. Second, in order to improve user satisfaction when a user is provided with vibrations when the touchscreen is touched, a vibration response speed should be increased, in accordance with a speed at which the screen is touched.
In this regard, a piezo haptic actuator has been used as a product able to provide such levels of performance. The piezo haptic actuator uses an inverse piezoelectric effect in which displacement is generated when a voltage is applied to a piezo-element, that is, a principle of allowing a mass body provided on a movable element to be moved by the generated displacement to generate vibration force.
A vibrator having the above-mentioned structure has the following features. A bandwidth of a frequency able to provide a predetermined level of vibration force or greater is wide, such that stable vibration characteristics may be implemented with the use thereof, and vibrations having low and high frequencies within a predetermined frequency range, rather than a single frequency, may be variously used. In addition, since the vibrator may implement rapid operational response characteristics, it may be appropriate for implementing haptic feedback vibrations in a mobile device such as a mobile phone, or the like.
Meanwhile, the piezo-element generally is formed to have a rectangular parallelepiped shape. In this case, since the length of the piezo-element should be relatively long, in order to secure displacement and vibrations, the entire length of the vibration generating apparatus increases and the piezo-element is vulnerable to external impacts, such as those caused by a product being dropped.
Further, since the overall shape of the vibration generating apparatus is a rectangular parallelepiped, the overall volume thereof may be increased, such that miniaturization of components may not be feasible.
In addition, the vibrator and a vibrating apparatus housing may come into contact with each other while being driven, or in the case of an external impact, to thereby cause noise.